Progress toward proof of the principal cause of insect mating disruption under a particular set of conditions has been hindered by a lack of logical rigor and clean falsifications of possible explanations. Here we make the case that understanding of mating disruption and optimization of particular formulations can be significantly advanced by rigorous application of the principles of strong inference. To that end, we offer a dichotomous key for eight distinct categories of mating disruption and detail criteria and methodologies for differentiating among them. Mechanisms of mating disruption closely align with those established for enzyme inhibition, falling into two major categories—competitive and noncompetitive. Under competitive disruption, no impairments are experienced by males, females, or the signal of females. Therefore, males can respond to females and traps. Competitive disruption is entirely a numbers game where the ratio of dispensers to females and traps is highly consequential and renders the control pest-density-dependent. Under noncompetitive disruption, males, females, or the signal from females are already impaired when sexual activity commences. The control achieved noncompetitively offers the notable advantage of being pest-density-independent. Dosage—response curves are the best way to distinguish competitive from noncompetitive disruption. Purely competitive disruption produces: a smoothly concave curve when untransformed capture data are plotted on the y-axis against density of dispensers on the x-axis; a straight line with positive slope when the inverse of catch is plotted against density of pheromone dispensers; and, a straight line with negative slope when catch is plotted against density of pheromone dispensers × catch. Disruption operating only noncompetitively produces: a straight line with negative slope when untransformed capture data are plotted on the y-axis against density of dispensers on the x-axis; an upturning curve when the inverse of catch is plotted against density of pheromone dispensers; and, a recurving plot when catch is plotted against density of pheromone dispensers x catch. Hybrid profiles are possible when some males within the population begin the activity period already incapacitated, while those not preexposed have the capacity to respond either to traps or pheromone dispensers. Competitive mechanisms include competitive attraction, induced allopatry, and induced arrestment. Noncompetitive mechanisms include desensitization and inhibition, induced allochrony, suppressed calling and mating, camouflage, and sensory imbalance. Examples of the various disruption types within the two major categories and suggested tactics for differentiating among them are offered as seven case studies of the disruption of important pest species using various formulations are analyzed in depth. We point out how economic optimizations may be achieved once the principal and contributory causes of disruption are proven. Hopefully, these insights will pave the way to a broader and more reliable usage of this environmentally friendly pest management tactic.

Information on dynamics of anopheline mosquitoes is limited in the coastal zone of French Guiana compared with inland endemic areas. Importantly, improvement of surveillance techniques for assessing malaria transmission indicators and comprehension of impact of meteorological factors on Anopheles darlingi Root, the main malaria vector, are necessary. Anopheline mosquitoes were collected continuously during 2012 and 2013 using Mosquito Magnet traps baited with octenol and human landing catches. The two methods were compared based on trends in abundance and parity rate of An. darlingi. Impact of meteorological factors on An. darlingi density estimates was investigated using Spearman's correlation and by binomial negative regression analysis. In all, 11,928 anopheline mosquitoes were collected, and 90.7% (n = 10,815) were identified consisting of four species, with An. darlingi making up 94.9% (n = 10,264). An. darlingi specimens collected by the two methods were significantly correlated, and no difference in parity rate was observed. The abundance of this species peaked in September (dry season) and variations along the years were influenced by relative humidity, temperature, rainfall, and wind speed. Number of mosquitoes collected during peak aggression period was influenced by wind speed and rainfall. Data gathered in this study provide fundamental information about An. darlingi, which can facilitate the design of vector control strategies and construction of models for predicting malaria risk.

The interaction between the arroyo willow, Salix lasiolepis Bentham, and its specialist herbivore, the arroyo willow stem-galling sawfly, Euura lasiolepis Smith (Hymenoptera: Tenthredinidae), was studied for 32 yr in Flagstaff, AZ, emphasizing a mechanistic understanding of insect population dynamics. Long-term weather records were evaluated to provide a climatic context for this study. Previously, predictive models of sawfly dynamics were developed from estimates of sawfly gall density made between 1981 and 2002; one model each for drier and wetter sites. Predictor variables in these models included winter precipitation and the Palmer Drought Severity Index, which impact the willow growth, with strong bottom-up effects on sawflies.We now evaluate original model predictions of sawfly population dynamics using new data (from 2003–2012). Additionally, willow resources were evaluated in 1986 and in 2012, using as criteria clone area, shoot density, and shoot length. The dry site model accounted for 40% of gall population density variation between 2003 and 2012 (69% over the 32 yr), providing strong support for the bottom-up, mechanistic hypothesis that water supply to willow hosts impacts sawfly populations. The current drying trend stressed willow clones: in drier sites, willow resources declined and gall density decreased by 98%. The wet site model accounted for 23% of variation in gall population density between 2003 and 2012 (48% over 30 yr), consistent with less water limitation. Nonetheless, gall populations were reduced by 72%.

The invasive brown marmorated stink bug, Halyomorpha halys (Stål), has caused severe economic losses in the United States and is also a major nuisance pest invading homes. In diverse woody plant nurseries, favored host plants may be attacked at different times of the season and in different locations in the field. Knowledge of factors influencing H. halys abundance and simple methods to predict where H. halys are found and cause damage are needed to develop effective management strategies. In this study, we examined H. halys abundance on plants in tree nurseries as a function of distance from field edges (edge and core samples) and documented the abundance in tree nurseries adjoining different habitat types (corn, soybean, residential areas, and production sod). We conducted timed counts for H. halys on 2,016 individual trees belonging to 146 unique woody plant cultivars at two commercial tree nurseries in Maryland. Across three years of sampling, we found that H. halys nymphs and adults were more abundant at field edges (0–5mfrom edges) than in the core of fields (15–20mfrom edges). Proximity of soybean fields was associated with high nymph and adult abundance. Results indicate that monitoring efforts and intervention tactics for this invasive pest could be restricted to field edges, especially those close to soybean fields. We show clearly that spatial factors, especially distance from edge, strongly influence H. halys abundance in nurseries. This information may greatly simplify the development of any future management strategies.

Adaptation of parasitoids to their phytophagous host is often mediated by environmental conditions and by the food plant of the phytophagous host. Therefore, the host food plant can indirectly affect the survival and fitness of parasitoids that also attack quiescent host stages, such as eggs, in which the resources available to the immature parasitoid stages are limited. Our aim was to investigate how two egg parasitoid species of the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermu¨ ller), respond to variations in egg traits at the extremes of a west-to-east geographic gradient in northern Italy. We considered one specialist [Baryscapus servadeii (Domenichini)] and one generalist [Ooencyrtus pityocampae (Mercet)] parasitoid, which reproduce mainly by thelytokous parthenogenesis and are common throughout the whole range of this pest. The size and shell structure of the pine processionary moth eggs were studied under light microscopy and tested experimentally under controlled conditions. We can conclude that 1) the pine processionary moth egg shell thickness is inversely proportional to the parasitism performance; 2) the larger eggs from the pine processionary moth eastern population produce parasitoid females of a larger size, which have greater realized fecundity; 3) the generalist parasitoid performs successfully with either the “home” or “away” (i.e., from both extremes of the geographic gradient) pine processionary moth eggs, which is not the case for the specialist parasitoid. The implications of these responses in the regulation of phytophagous populations are numerous and should be considered in population dynamics studies and pest management programs.

Soybean, Glycine max (L.) Merrill, flowers can be a source of nectar and pollen for honey bees, Apis mellifera L. (Hymenoptera: Apidae), wild social and solitary bees (Hymenoptera: Apoidea), and flower-visiting flies (Diptera). Our objectives were to describe the pollinator community in soybean fields, determine which sampling method is most appropriate for characterizing their abundance and diversity, and gain insight into which pollinator taxa may contact soybean pollen. We compared modified pan traps (i.e., bee bowls), yellow sticky traps, and sweep nets for trapping pollinators in Iowa soybean fields when soybeans were blooming (i.e., reproductive stages R1–R6) during 2011 and 2012. When all trap type captures were combined, we collected 5,368 individuals and at least 50 species. Per trap type, the most pollinators were captured in bee bowls (3,644 individuals, 44 species), yellow sticky traps (1,652 individuals, 32 species), and sweep nets (66 individuals, 10 species). The most abundant species collected include Agapostemon virescens F. and Lasioglossum (Dialictus) species (Hymenoptera: Halictidae), Melissodes bimaculata Lepeletier (Hymenoptera: Apidae), and Toxomerus marginatus Say (Diptera: Syrphidae). To determine if these pollinators were foraging on soybean flowers, we looked for soybean pollen on the most abundant bee species collected that had visible pollen loads. We found soybean pollen alone or intermixed with pollen grains from other plant species on 29 and 38% of the bees examined in 2011 and 2012, respectively. Our data suggest a diverse community of pollinators—composed of mostly native, solitary bees—visit soybean fields and forage on their flowers within Iowa.

Moths exhibit different levels of fidelity to habitat, and some taxa are considered as bioindicators for conservation because they respond to habitat quality, environmental change, and vegetation types. In this study, we verified the effect of two phytophysiognomies of the Cerrado, savanna and forest, on the diversity distribution of moths of Erebidae (Arctiinae), Saturniidae, and Sphingidae families by using a hierarchical additive partitioning analysis. This analysis was based on two metrics: species richness and Shannon diversity index. The following questions were addressed: 1) Does the beta diversity of moths between phytophysiognomies add more species to the regional diversity than the beta diversity between sampling units and between sites? 2) Does the distribution of moth diversity differ among taxa? Alpha and beta diversities were compared with null models. The additive partitioning of species richness for the set of three Lepidoptera families identified beta diversity between phytophysiognomies as the component that contributed most to regional diversity, whereas the Shannon index identified alpha diversity as the major contributor. According to both species richness and the Shannon index, beta diversity between phytophysiognomies was significantly higher than expected by chance. Therefore, phytophysiognomies are the most important component in determining the richness and composition of the community. Additive partitioning also indicated that individual families of moths respond differently to the effect of habitat heterogeneity. The integrity of the Cerrado mosaic of phytophysiognomies plays a crucial role in maintaining moth biodiversity in the region.

Olives, Olea europaea L., are one of the most important crops in Spain. They are currently produced under three management systems that involve different aspects of soil and pest management, productivity, and crop economy: organic, (integrated pest management—IPM), and conventional. Here, we studied how these systems affect the spiders, the natural enemies of olive grove pests, and performed a detailed analysis of their assemblage. The study was performed during one season in 18 olive groves in Andalusia, Spain, and included both ground-dwelling and canopy species.We found that the organic system supported a significantly higher level of abundance and diversity of canopy spiders than the IPM and conventional systems. Plowing had a negative effect on spider abundance and diversity. However, the presence of hedge vegetation had a positive effect on the spiders. The practices affected the guild structure differently, with some guilds supported by organic and others by IPM. It is suggested that sustainability (in terms of pest control) in olive grove agroecosystems may be obtained by maintaining hedge vegetation regardless of the management system.

Species interactions are often context dependent, where outcomes vary in response to one or more environmental factors. It remains unclear how abiotic conditions like temperature combine with biotic factors such as consumer density or food quality to affect resource availability or influence species interactions. Using the large grasshopper Melanoplus bivittatus (Say) and a common wolf spider [Rabidosa rabida (Walkenaer)], we conducted manipulative field experiments in tallgrass prairie to examine how spider—grasshopper interactions respond to manipulations of temperature, grasshopper density, and food quality. Grasshopper survival was density dependent, as were the effects of spider presence and food quality in context-dependent ways. In high grasshopper density treatments, predation resulted in increased grasshopper survival, likely as a result of reduced intraspecific competition in the presence of spiders. Spiders had no effect on grasshopper survival when grasshoppers were stocked at low densities. Effects of the experimental treatments were often interdependent so that effects were only observed when examined together with other treatments. The occurrence of trophic cascades was context dependent, where the effects of food quality and spider presence varied with temperature under high-density treatments. Temperature weakly affected the impact of spider presence on M. bivittatus survivorship when all treatments were considered simultaneously, but different context-dependent responses to spider presence and food quality were observed among the three temperature treatments under highdensity conditions. Our results indicate that context-dependent species interactions are common and highlight the importance of understanding how key biotic and abiotic factors combine to influence species interactions.

The effects of production practices on the relative abundance of springtails (Collembola) in irrigated cotton fields of northern New South Wales (NSW) were studied over 2 yr to examine effects of farmmanagement on these decomposer organisms. Pitfall trapping and soil core extraction was undertaken in both pseudoreplicated plots within whole fields on cotton farms and on experimental replicate plots of Envirofeast cotton and Lucerne. The relative abundance of surface-active springtails in cotton rows and densities of soil species from the rhizosphere were calculated. Twenty-three species of Collembola were collected from 5 fields, 19 in pitfall traps, and 11 in soil cores. Five species, Setogaster sp., Proisotoma minuta, Entomobrya unostrigata, Entomobrya multifasciata grp, and Lepidobrya sp. were numerically dominant on the ground at 86–96% of individuals and Mesaphorura sp., Folsomides parvulus, and Hemisotoma thermophila grp dominant in the soil. Native grassland samples contained 15 species of which a probable 10 were native and 8 were not found in cotton. Nineteen species of the 24 species identified from cotton were predominantly fungal feeders. Highest catches of Collembola occurred after flowering and soil Collembola increased with depth and during cotton growth on unsprayed plots but decreased on sprayed plots. Surface soil moistures affected daily catch rates with decomposing residues, crop stage, predator abundance, and season as secondary factors. Insecticide (endosulfan, pyrethroid, carbamate, and organophosphate) and predator effects were either negligible or unclear depending on the factor involved. Springtails appear to be predominately food limited during times of adequate soilmoisture in cotton fields.

Termites are major plant decomposers in tropical forest ecosystems, but their cryptic nature poses an obstacle for studying their ecological roles in depth. In the current study, we quantified climatic and geographic information of 137 termite collection sites in the Kenting National Park, Taiwan, and described the ecological niches and assemblage patterns of 13 termite species of three families. Three major assemblage patterns are reported. First, the three termite families were found in most landcovering types with similar number of species, which indicated that each family played a unique role in the ecosystem. Second, average numbers of termite species were not different among collection sites, but the total number of termite species found in each landcovering type was different, which indicated that termite niche capacity in each small area was the same but some landcovering types were composed of diverse microhabitats to host more termite species. Third, termite species of every family showed distinct moisture preferences in their habitat choices. In addition to the three assemblage patterns, we found that niche size of the advanced termite family, Termitidae, was larger than that of the primitive termite families, Rhinotermitidae or Kalotermitidae. The broader choices of cellulosic materials as food sources may allow Termitidae to adapt to more diverse environments than exclusive wood feeders. Termite niche quantification could further be used to study termite pest adaption in urban areas, interspecific competition between native and invasive species, and plant decomposition processes.

Row spacing in agricultural systems can influence crop yield as well as pest and predator abundances. Soybean (Glycine max L. Merrill) growers in Maryland typically plant in narrow (∼19 cm), medium (∼38 cm), or wide (∼76 cm)-spaced rows, and there is a general lack of information on how these row-spacing schemes influence arthropod abundance and soybean yields. A study was conducted during two growing seasons to determine the effect of soybean row spacing and planting date (early and late) on soybean arthropods and yield. Despite a great deal of variation in arthropod responses to row spacing, and interactions between row spacing and study year, leaf-feeding herbivores were generally more abundant in narrow-spaced soybeans. All arthropod functional groups were more abundant, and yield was greater in early-planted soybeans relative to late-planted soybeans. Potential causes and implications of these finding are discussed.

The diversity of vectors and fleeting nature of virus acquisition and transmission renders nonpersistent viruses a challenge to manage. We assessed the importance of noncolonizing versus colonizing vectors with a 2-yr survey of aphids and nonpersistent viruses on commercial pumpkin farms.We quantified aphid alightment using pan traps, while testing leaf samples with multiplex RT-PCR targeting cucumber mosaic virus (CMV), zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and papaya ringspot virus (PRSV). Overall, we identified 53 aphid species (3,899 individuals), from which the melon aphid, Aphis gossypii Glover, a pumpkin-colonizing species, predominated (76 and 37% of samples in 2010 and 2011, respectively). CMV and ZYMV were not detected, but WMV and PRSV were prevalent, both regionally (WMV: 28/29 fields, PRSV: 21/29 fields) and within fields (infection rates = 69 and 55% forWMVin 2010 and 2011; 28 and 25% for PRSV in 2010 and 2011). However, early-season samples showed extremely low infection levels, suggesting cucurbit viruses are not seed-transmitted and implicating aphid activity as a causal factor driving virus spread. Interestingly, neither noncolonizer and colonizer alightment nor total aphid alightment were good predictors of virus presence, but community analyses revealed species-specific relationships. For example, cowpea aphid (Aphis craccivora Koch) and spotted alfalfa aphid (Therioaphis trifolii Monell f. maculata) were associated with PRSV infection, whereas the oleander aphid (Aphis nerii Bover de Fonscolombe) was associated with WMV spread within fields. These outcomes highlight the need for tailored management plans targeting key vectors of nonpersistent viruses in agricultural systems.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), invokes substantial chemical treatment and economic cost in North America. Resistant soybean genotypes hold promise as a low-impact control methodology, but soybean aphid “biotypes” capable of development on resistant soy cast doubt on the durability of soy resistance. We hypothesized that variation in soybean aphid ability to colonize resistant soy is partially attributable to a bacterial symbiont of soybean aphid, Arsenophonus. We used microinjection to manipulate Arsenophonus infection in both virulent and avirulent aphid biotypes, resulting in five pairs of infected versus uninfected isolines. These isolines were subjected to various population growth rate assays on resistant Rag versus susceptible soybean. We found that aphid virulence on Rag soybean was not dependent on Arsenophonus: virulent aphid biotypes performed well on Rag soybean, and avirulent aphid biotypes performed poorly on Rag soybean, regardless of whether Arsenophonus was present or not. However, we did find that Arsenophonus-infected clones on average performed significantly better than their paired uninfected isolines. This pattern was not consistently evident on every date for every clone, either in the population assays nor when we compared lifetime fecundity of individual aphids in a separate experiment. Nevertheless, this overall benefit for infected aphids may be sufficient to explain the high frequency of Arsenophonus infection in soybean aphids.

The specific primers of five species of endosymbiotic bacteria were designed to determine their numbers in three virulent populations of brown planthopper, Nilapavata lugens Stål, and to assess changes during adaptation to different resistant varieties using fluorescent quantitative PCR. The results showed that Chryseobacterium was the dominant bacteria in all three populations of brown planthopper, followed by Acinetobacter in TN1 population, Arsenophonus and Serratia in Mudgo population, and Arthrobacter and Acinetobacter in ASD7 population. When the TN1 population of brown planthopper was transferred to ASD7 (with resistant gene bph2) rice plants, Chryseobacterium was still the dominant bacteria, but the originally subdominant Acinetobacter declined to a level that was not significantly different from that of other endosymbiotic bacteria. After they were transferred to Mudgo (with resistant gene Bph1), Serratia and Arsenophonus increased significantly and became the dominant bacteria. However, they declined to a level that was not significantly different from that of the three other species after two generations. When ASD7 and Mudgo populations of brown planthopper were transferred to the susceptible variety TN1, the community of endosymbiotic bacteria in the ASD7 population of brown planthopper showed no significant changes. However, the numbers of Acinetobacter and Arthrobacter in the Mudgo population of brown planthopper exhibited a transient increase and returned to their original levels after two generations. After the Mudgo population of brown planthopper was transferred to ASD7 rice plants, the quantity of endosymbiotic bacteria fluctuated, but the bacterial structure did not change significantly. However, after the ASD7 population of brown planthopper was transferred to the Mudgo rice plants, the bacterial structure changed significantly. Serratia and Arsenophonus increased significantly and became dominant. Although Serratia and Arsenophonus decreased significantly after a generation, they were still greater than Chryseobacterium. It was presumed that Chryseobacterium was dominant in all three populations of virulent brown planthoppers, but had no significant effect on virulence variation of brown planthopper. However, Serratia and Arsenophonus might be correlated with virulence variation of brown planthopper.

Defensive symbiosis is amongst nature's most important interactions shaping the ecology and evolution of all partners involved. The pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae), harbors one obligatory bacterial symbiont and up to seven different facultative symbionts, some of which are known to protect the aphid from pathogens, natural enemies, and other mortality factors. Pea aphids typically drop off the plant when a mammalian herbivore approaches it to avoid incidental predation. Here, we examined whether bacterial symbionts govern the pea aphid dropping behavior by comparing the bacterial fauna in dropping and nondropping aphids of two A. pisum populations, using two molecular techniques: high-throughput profiling of community structure using 16 S reads sequenced on the Illumina platform, and diagnostic polymerase chain reaction (PCR).We found that in addition to the obligatory symbiont, Buchnera aphidicola, the tested colonies of A. pisum harbored the facultative symbionts Serratia symbiotica, Regiella insecticola and Rickettsia, with no significant differences in infection proportions between dropping and nondropping aphids. While S. symbiotica was detected by both techniques, R. insecticola and Rickettsia could be detected only by diagnostic PCR. We therefore conclude that A. pisum's dropping behavior is not affected by its bacterial symbionts and is possibly affected by other factors.

Potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), is an economic pest of solanaceous crops in North and Central America, and in New Zealand. Four genetic haplotypes of the psyllid have been identified in North America. Three of these haplotypes (Central, Western, and Northwestern) are common on potato crops within the major potato-growing regions of Idaho, Oregon, and Washington. Within this growing region, a weedy perennial nightshade, Solanum dulcamara (bittersweet nightshade), has been identified to be an important overwintering host and spring or summer source of psyllids colonizing potato fields. It is unclear whether bittersweet nightshade is a highly suitable host plant for all three haplotypes known to occur in the Pacific Northwest. The objective of the present study was to examine developmental traits and adult body size of all three haplotypes of psyllids reared on potato and bittersweet nightshade. Averaged over haplotype, development times were longer for psyllids reared on nightshade than potato. Duration of the preoviposition period, egg incubation requirements, nymphal development time, and total developmental time averaged 7.4, 5.9, 23.5, and 29.5 d on nightshade and 4.9, 5.5, 22.3, and 27.9 d on potato, respectively. The largest host effects were found for the Central haplotype, which exhibited a substantially extended (by over 5 d) preoviposition period on nightshade compared with potato. Averaged over host plant, nymphal and total development times of the Northwestern haplotype were longer (25.5 and 31.1 d, respectively) than those of the Western and Central haplotypes. The Northwestern haplotype was largest in overall body size, while the Central haplotype had the smallest overall body size, irrespective of host plant. Both sexes exhibited this trend.

Gall-inducing insects are known for altering source—sink relationships within plants. Changes in photosynthesis may contribute to this phenomenon. We investigated photosynthetic responses in wheat [Triticum aestivum L. (Poaceae: Triticeae)] seedlings attacked by the Hessian fly [Mayetiola destructor (Say) (Diptera: Cecidomyiidae], which uses a salivary effector-based strategy to induce a gall nutritive tissue in susceptible plants. Resistant plants have surveillance systems mediated by products of Resistance (R) genes. Detection of a specific salivary effector triggers downstream responses that result in a resistance that kills neonate larvae. A 2 × 2 factorial design was used to study maximum leaf photosynthetic assimilation and stomatal conductance rates. The plant treatments were—resistant or susceptible wheat lines expressing or not expressing the H13 resistance gene. The insect treatments were—no attack (control) or attack by larvae killed by H13 gene-mediated resistance. Photosynthesis was measured for the second and third leaves of the seedling, the latter being the only leaf directly attacked by larvae. We predicted effector-based attack would trigger increases in photosynthetic rates in susceptible but not resistant plants. For susceptible plants, attack was associated with increases (relative to controls) in photosynthesis for the third but not the second leaf. For resistant plants, attack was associated with increases in photosynthesis for both the second and third leaves. Mechanisms underlying the increases appeared to differ. Resistant plants exhibited responses suggesting altered source—sink relationships. Susceptible plants exhibited responses suggesting a mechanism other than altered source—sink relationships, possibly changes in water relations that contributed to increased stomatal conductance.

Frost is known to directly affect flowering wheat plants (Triticum aestivum L.) and lead to reduced grain yield. Additionally, it may increase wheat susceptibility to economically important pests, such as aphids (Hemiptera: Aphididae). Wheat plants at flowering stage were exposed to one of the three temperature treatments: ambient (11–12°C), 0°C, and -3°C for 60 min. Preference (3-choice) and performance (no-choice) bioassays with aphids (Rhopalosiphum padi L.) were conducted 1, 3, 6, and 12 d after temperature treatments to assess effects of temperature-induced stress over time. As an initial feasibility study of using remote sensing technologies to detect frost-induced stress in flowering wheat plants, hyperspectral imaging data were acquired from wheat plants used in preference bioassays. Element analysis of wheat plants was included to determine the effect of temperature-induced stress on the nutritional composition of flowering wheat plants. The results from this study support the following cause-effect scenario: a 60-min exposure to low temperatures caused a significant decrease in potassium and copper content of wheat plants 6 d after temperature exposure, and it coincided with a marked increase in preference by aphids of wheat plants. The preference exhibited by aphids correlated positively with performance of aphids, so the preference—performance hypothesis was confirmed and possibly driven by potassium and copper content of wheat plants. In addition, we demonstrated that hyperspectral imaging data can be used to detect frost-induced susceptibility to aphid infestation in flowering wheat plants. These findings justify further research into airborne remote sensing of frost-induced stress and the possible secondary effects on crop susceptibility to arthropod pests.

Members of the Miridae (Lygus lineolaris Palisot de Beauvois and Pseudatomoscelis seriatus Reuter) and Pentatomidae (Acrosternum hilare Say, Euschistus servus (Say), Euschistus tristigmus (Say), Euschistus quadrator Rolston, Oebalus pugnax (F.), Piezodorus guildinii (Westwood), and Thyanta custator accerra McAtee) comprise a piercing—sucking insect complex that continues to plague multiple crops, including cotton. All these species have been associated with pathogen transmission. Breaching of boll carpel walls facilitates introduction of pathogens, and it is unknown whether stylets of these pests can fully penetrate carpel walls. Thus, stylet penetration estimates are needed and have been the focus of the present work. Stylet penetration estimates for L. lineolaris were significantly deeper than P. seriatus. Among the Pentatomidae, highest mean penetrationwas estimated for E. servus followed by A. hilare, yet A. hilare possessed a longer rostrum. Similarly, O. pugnax showed deeper penetration estimates than P. guildinii yet P. guildinii possessed a longer rostrum. Thus, rostrum length should not be equated to penetration potential. Pseudatomoscelis seriatus and L. lineolaris both infest early-season cotton, and the ranges of observed penetration indicate these insects, as well as the Pentatomidae, can breach the walls of critical pinhead squares and smaller bolls. The insects addressed herein affect a myriad of crops globally, and penetration estimates allow identification of growth stages susceptible to feeding and disease transmission.

Plant domestication can have negative consequences for defensive traits against herbivores, potentially reducing the levels of chemical defenses in plants and consequently their resistance against herbivores.We characterized and quantified the defensive flavonols frommultiple cultivated ecotypes with wild ancestors of murtilla, Ugni molinae Turcz, an endemic plant from Chile, at different times of the year, and examined their effects on a native insect herbivore, Chilesia rudis Butler (Lepidoptera: Arctiidae). We hypothesized that domestication results in a decrease in flavonol levels in U. molinae plants, and that this negatively affected C. rudis performance and preference. Ethanolic extracts were made from leaves, stems, and fruit of murtilla plants for flavonol analysis. Flavonols identified were kaempferol, quercetin, rutin, and quercetin 3-D-β-glucoside, the last two being themost abundant.More interestingly, we showed differences in flavonol composition between wild and cultivated U. molinae that persisted for most of the year. Relative amounts of all four flavonols were higher in wild U. molinae leaves; however, no differences were found in the stem and fruit between wild and cultivated plants. In choice and no-choice assays, C. rudis larvae gained more mass on, and consumed more leaf material of, wild as compared with cultivated U. molinae plants.Moreover, when applied to leaves, larvae ate more leaf material with increasing concentrations of each flavonol compound. Our study demonstrates that domestication in U. molinae reduced the amount of flavonols in leaves as well as the performance and preference of C. rudis, indicating that these compounds stimulate feeding of C. rudis.

Wildlife-friendly gardening practices can help conserve biodiversity in urban areas. These include growing ornamental plant varieties attractive to flower-visiting insects. Because varieties vary greatly in attractiveness, there is a need to quantify it in order to give objective advice to gardeners. Here, we used the British national collection of asters to compare the attractiveness of varieties to flower-visiting insects. We counted and identified insects as they foraged on flowers in 228 varieties growing in discrete patches that flowered during the survey period, 14 September–20 October 2012. In each variety, we also determined the overall capitulum size, the central disc floret area, and the ray floret color (blue, red, purple, or white). We also scored attributes relevant to gardening: attractiveness to humans, ease of cultivation, and availability in the United Kingdom. There was great variation among varieties in their attractiveness to insects, ranging from 0.0 to 15.2 per count per square meter, and highly skewed, with most being unattractive. A similar skew held for the two main insect categories, honey bees and hover flies, which comprised 28 and 64% of all insects, respectively. None of the floral traits or attributes relevant to gardening correlated significantly with attractiveness to insects. Our study shows the practicality of using a national collection for quantifying and comparing the attractiveness of ornamental varieties to flower-visiting insects. These results imply that choosing varieties carefully is likely to be of conservation benefit to flower-visiting insects, and that doing so is a no-cost option in terms of garden beauty and workload.

European buckthorn (Rhamnus cathartica L.) is an invasive woody shrub in deciduous forests of the Upper Midwest. Studies have suggested buckthorn invasion has negative effects on native plants, soil, and ecosystems, but its impacts on insects are largely unstudied. To test the impact of buckthorn invasion on ground-dwelling insects in forests of northeastern Iowa, pitfall traps were used to sample ground-dwelling insects at five sites four different periods from June to August 2013. Each site had three treatments: areas heavily infested with buckthorn, areas where buckthorn has not established, and areas where buckthorn had been removed within the past 2–10 yr. Most insects were identified to family and quantified; while ground beetles (Coleoptera: Carabidae) and ants (Hymenoptera: Formicidae) were identified to species and quantified. In total, 11,576 insects representing eight orders and 46 families were collected. Areas uninvaded by buckthorn had significantly greater insect abundance and taxonomic richness than areas invaded by buckthorn. Of the 948 ground beetles representing 40 species, abundance, species richness, and Shannon diversity indices were significantly lower in areas invaded by buckthorn compared with areas with no buckthorn. The 2,661 ants from 24 species had similar trends, but treatment differences were not significant because of high variability. These results clearly show a negative impact of buckthorn invasion on the abundance and taxonomic richness of ground-dwelling insects.

Observations of virulent Aphis glycines Matsumura populations on resistant soybean in North America occurred prior to the commercial release of Rag genes. Laboratory assays confirmed the presence of four A. glycines biotypes in North America defined by their virulence to the Rag1 and Rag2 genes. Avirulent and virulent biotypes can co-occur and potentially interact on soybean, which may result in induced susceptibility. We conducted a series of experiments to determine if the survival of avirulent biotypes on susceptible and resistant soybean containing the Rag1 or Rag1 Rag2 genes was affected by the presence of either avirulent or virulent conspecifics. Regardless of virulence to Rag genes, initial feeding by conspecifics increased the survival of subsequent A. glycines populations on both susceptible and resistant soybean. Avirulent populations increased at the same rate as virulent populations if the resistant plants were initially colonized with virulent aphids. These results are the first to demonstrate that virulent A. glycines increase the suitability of resistant soybean for avirulent conspecifics, thus explaining the lack of genetic differentiation observed in North America between A. glycines populations on resistant and susceptible soybean. These results suggest the occurrence of virulence toward Rag genes in North America may be overestimated. In addition this may alter the selection pressure for virulence genes to increase in a population. Therefore, insect resistance management models for A. glycines may need to incorporate induced susceptibility factors to determine the relative durability of resistance genes.

Crapemyrtle is a common landscape planting that is a resource subsidy for beneficial insects. Field studies were conducted to determine the influence of crapemyrtle flower color on the population abundances and predator—prey dynamics of the herbivorous Frankliniella species and the predator Orius insidiosus. Adults and immatures of predator and prey were highly anthophilous, preferring white ‘Acoma' flowers compared with lavender ‘Apalachee', red ‘Carolina Beauty', and pink ‘Choctaw'. The predator was aggregated with its prey in a density-dependent manner: the adults by preferring the crapemyrtle clones also preferred by the thrips and the nymphs by direct tracking or as a function of increased prey and fecundity. Acoma was best for preference and buildup of O. insidiosus populations, and it was the only clone where there was no buildup in thrips populations. Two species of Karnyothrips (Thysanoptera: Phlaoethripidae), predators of small insects, were common in Tillandsia usneoides, an epiphyte on the crapemyrtle. Crapemyrtle is a bridge to enhance populations of O. insidiosus during summer months when there are few other hosts in the southern USA.

Many animals use pheromone marking as a way to identify their territory or other resources. Among insects, substrate-borne marking is frequently reported for females, which in many species make marks containing oviposition-deterring pheromone, which other females avoid. However, there are fewer reports of substrate-borne marking for males. Here, marking in males of the parasitoid wasp Urolepis rufipes (Ashmead) is described. The conditions under which males mark and whether males and females respond to the males' marks were examined using behavioral observations. Males marked by dragging the tips of their abdomens across a substrate. They marked much more after mating and after consuming honey. They also marked more when with a female, irrespective of copulation, although not when with a male. Females spent more time on or near marked substrates, and males also responded to their own marks. Although males aggressively and successfully defended areas that they had marked against other males, males did not respond to another male's marks in the conspecific's absence. In contrast to males, females did not mark, either on the surface of hosts or on other surfaces, and males showed no detectable response to surfaces which females had recently occupied.

Spalangia endius (Walker) (Hymenoptera: Pteromalidae) is found to be one of the most important natural enemies of Bactrocera dorsalis Hendel (Diptera: Tephritidae) pupae in China. In this study, the influence of host pupal age on the preference for and suitability of the host by the parasitoid S. endius was determined using choice and nonchoice tests. S. endius females accepted the 1–7 d-old B. dorsalis pupae for oviposition, and their offspring developed successfully. However, the S. endius preferentially parasitized the 2-, 3-, and 4-d-old host pupae. The emergence rate of the adult progeny was not affected by the host pupal age, nor was the male body weight, male longevity, and sex ratio of the parasitoid offspring. However, the shortest development time of both male and female progeny and the greatest size and adult longevity of female progeny were observed in hosts that were ≤4 d old. Females emerged later and lived longer than males, and they weighed more than the males. Host mortality decreased as the age of the host increased for 1–7-d-old hosts. Our findings suggest that 2-, 3-, and 4-d-old B. dorsalis pupae would be the best host ages at which to rear S. endius for effective control in field releases.

Measuring and modeling the attractiveness of semiochemical-baited traps is of significant importance to detection, delimitation, and control of invasive pests. Here, we describe the results of field mark—release—recapture experiments with Ceratitis capitata (Wiedemann) and Bactrocera dorsalis (Hendel) to estimate the relationship between distance from a trap baited with trimedlure and methyl eugenol, respectively, and probability of capture for a receptive male insect. Experiments were conducted using a grid of traps with a central release point at two sites on Hawaii Island, a Macadamia orchard on the East side of the island and a lava field on theWest side.We found that for B. dorsalis and methyl eugenol there is a 65% probability of capture at ∼36m from a single trap, regardless of habitat. For C. capitata, we found a 65% probability of capture at a distance of ∼14m from a single trap in the orchard and 7 m in the lava field. We also present results on the spatial and temporal pattern of recaptures. The attraction data are analyzed via a hyperbolic secant-based capture probability model.

Drosophila suzukii Matsumara, also referred to as the spotted wing drosophila, has recently expanded its global range with significant consequences for its primary host crops: blueberries, blackberries, raspberries, cherries, and strawberries. D. suzukii populations can increase quickly, and their infestation is difficult to predict and prevent. The development of effective tools to detect D. suzukii presence in new areas, to time the beginning of activity within a crop, to track seasonal activity patterns, and to gauge the effectiveness of management efforts has been a key research goal. We compared the efficiency, selectivity, and relationship to fruit infestation of a range of commonly used homemade baits and a synthetic formulated lure across a wide range of environments in 10 locations throughout the United States. Several homemade baits were more efficient than apple cider vinegar, a commonly used standard, and a commercially formulated lure was, in some configurations and environments, comparable with the most effective homemade attractant as well as potentially more selective. All alternative attractants also captured flies between 1 and 2 wk earlier than apple cider vinegar, and detected the presence of D. suzukii prior to the development of fruit infestation. Over half the Drosophila spp. flies captured in traps baited with any of the attractants were not D. suzukii, which may complicate their adoption by nonexpert users. The alternative D. suzukii attractants tested are improvement on apple cider vinegar and may be useful in the development of future synthetic lures.

Chemical communication is necessary to induce aggregation and to maintain the cohesion of aggregates in Periplaneta americana (L.) cockroaches. We aimed to identify the chemical message inducing aggregation in this species. Two types of bioassays were used—binary choice tests in Petri dishes and tests in Y-olfactometer. Papers conditioned by direct contact of conspecifics induce aggregation when proposed in binary choice tests and were attractive in a Y-olfactometer. The identification of the molecules present on these conditioned papers indicated that dichloromethane extracts contained mainly cuticular hydrocarbons whereas methanol extracts contained more volatile molecules. Only a mixture of extracts in both solvents induced aggregation. High concentrations of cuticular hydrocarbons are necessary to induce aggregation when presented alone. When presented with volatile molecules present in methanol extracts, low concentrations of cuticular hydrocarbons are sufficient to induce aggregation if they are presented in contact. Among volatile molecules collected on filter paper, a mixture of three compounds—hexadecanoic acid, pentadecanoic acid, and pentaethylene glycol—induced aggregation. Our results provide evidence that aggregation processes in P. americana relies on a dual mechanism: attraction over long distances by three volatile molecules and maintenance on site by contact with cuticular hydrocarbons.

The attractiveness of a series of mixtures of (Z)-7-dodecenyl acetate (Z7-12:Ac), (Z)-9-tetradecenyl acetate (Z9-14:Ac), and (Z)-11-hexadecenyl acetate (Z11-16:Ac), the Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) pheromone, were evaluated in four locations in China. The ternary blend of Z7-12:Ac, Z9-14:Ac, and Z11-16:Ac was the complete pheromone blend for A. ipsilon and the ratio of Z7-12:Ac and Z9-14:Ac was optimal at 3:1. The most attractive ratio of Z11-16:Ac to the other components depended on geographic location. The optimal ratio was 3:1:6 in Yunnan and Shanxi, 3:1:2 in Sichuan and ranged from 3:1:2 to 3:1:12 in Shanghai, which differs significantly from the ratio of 3:1:16 in Japan. The dose of the blend in the pheromone lure influenced attractiveness to male moths and was related to the temperature in the test locations. Attractiveness of sugar—acetic acid-baited and pheromone-baited traps to male and female moths was different before and after the start of flowering of the oilseed rape crop; large numbers of female moths were attracted to sugar—acetic acid traps before flowering but none after flowering had started. This was similar for male moths and there was no synergistic effect when sugar—acetic acid solutions and pheromone were used together. These studies suggest that pheromone trapping based on the blends of three components can be an effective tool to improve the efficiency of monitoring of this pest in China.

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a devastating insect pest in its introduced range. A trapping system that increases trap catches or detection rates in low-density populations would be beneficial for survey programs. Five trapping experiments were conducted to investigate factors influencing capture rates of male beetles on dark green traps baited with the A. planipennis pheromone, (3Z)-dodecen-12-olide ((3Z)-lactone), plus the green leaf volatile, (3Z)-hexenol. Low doses (0.001–1.0 mg) of (3Z)-lactone (3Z)-hexenol did not consistently increase captures of male A. planipennis. In other experiments, mean captures of males were significantly higher on traps baited with a moderate dose (3.0 mg/septum) of (3Z)-lactone (3Z)-hexenol, compared with lower doses (0.001, 0.1, and 1.0 mg) or (3Z)-hexenol alone. Next, we demonstrated that addition of (3Z)-lactone to traps baited with (3Z)-hexenol resulted in significantly greater increases in male captures when pairs of traps were placed on the same tree, than when traps were placed on adjacent trees. Moreover, significantly more A. planipennis were captured on pheromone-baited traps placed in the southern versus northern aspect of the crown. These results highlight the importance of experimental set-up for elucidating lure treatment effects and also suggests the (3Z)-lactone may be more active at close range. Our findings increase our understanding of the pheromone ecology of this species and lend support toward the use of dark green traps baited with 3.0 mg (3Z)-lactone (3Z)-hexenol deployed in the south aspect of the canopy for detection programs for this insect.

A recent identification of the two-component aggregation pheromone of the invasive stink bug species, Halyomorpha halys (Stål), in association with a synergist, has greatly improved the ability to accurately monitor the seasonal abundance and distribution of this destructive pest. We evaluated the attraction of H. halys to black pyramid traps baited with lures containing the pheromone alone, the synergist methyl (2E,4E,6Z)-decatrienoate (MDT) alone, and the two lures in combination. Traps were deployed around areas of agricultural production including fruit orchards, vegetables, ornamentals, or row crops in Delaware, Maryland, North Carolina, New Jersey, New York, Ohio, Oregon, Pennsylvania, Virginia, and West Virginia from mid-April to mid-October, 2012 and 2013. We confirmed that H. halys adults and nymphs are attracted to the aggregation pheromone season long, but that attraction is significantly increased with the addition of the synergist MDT. H. halys adults were detected in April with peak captures of overwintering adults in mid- to late May. The largest adult captures were late in the summer, typically in early September. Nymphal captures began in late May and continued season long. Total captures declined rapidly in autumn and ceased by mid-October. Captures were greatest at locations in the Eastern Inland region, followed by those in the Eastern Coastal Plain and Pacific Northwest. Importantly, regardless of location in the United States, all mobile life stages of H. halys consistently responded to the combination of H. halys aggregation pheromone and the synergist throughout the entire season, suggesting that these stimuli will be useful tools to monitor for H. halys in managed systems.

The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an invasive pest of sugarcane, Saccharum spp., rice, Oryza sativa L., and other graminaceous crops in the Gulf Coast region of the United States. Traps baited with E. loftini female sex pheromones were used to document establishment and distribution of E. loftini near sugarcane, rice, and noncrop hosts in seven southwest Louisiana parishes from 2009 to 2013. Additional field surveys documented larval infestations in commercial sugarcane and rice. After its initial detection in 2008, no E. loftini were detected in Louisiana in 2009 and only two adults were captured in 2010. Trapping documented range expansion into Cameron, Beauregard, and Jefferson Davis parishes in 2011 and Allen, Acadia, and Vermilion parishes in 2013. During the course of this study, E. loftini expanded its range eastward into Louisiana 120 km from the Texas border (≈22 km/yr). Surveys of larval infestations provided the first record of E. loftini attacking rice and sugarcane in Louisiana. Infestations of E. loftini in rice planted without insecticidal seed treatments in Calcasieu Parish reached damaging levels.

Characterization of spatial distribution patterns of pests in large-scale agricultural fields is important because these patterns affect the sampling effort needed to accurately detect and estimate their population density. In this study, we conducted experimental releases of alate cabbage aphids (Brevicoryne brassicae L.) into centers of small plots of canola (Brassica napus L.), and their gradual spread over a 7-wk period was characterized. The small-plot experiment demonstrated gradient effects from plot centers and a nonrandom vertical distribution, with initial colonization occurring on the abaxial side of lower canopy leaves and, later, highest numbers of cabbage aphids occurring on racemes.We also conducted large-scale distribution analyses of cabbage aphid infestations in two commercial canola fields, using visual inspection and sweep net sampling. We used canola plant phenological and landscape features as explanatory variables of the spatial distribution of cabbage aphid counts. These large-scale experiments showed strong edge effects with negative associations between cabbage aphid counts and distance to crop edges, including tree lines and contour banks. Cabbage aphid distribution was more effectively displayed using logistic regression than ordinary regression, Spatial Analysis by Distance IndicEs, or both. Based on the study findings, a nonrandom or optimized inspection approach is proposed to focus monitoring efforts on canola plants within 20 m from field edges with particular attention to the abaxial side of lower-canopy leaves. Detection of advanced cabbage aphid infestations should target the racemes within 20 m from field edges.

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is a key pest of citrus due to its role as vector of citrus greening disease or “huanglongbing.” ACP monitoring is considered an indispensable tool for management of vector and disease. In the present study, datasets collected between 2009 and 2013 from 245 citrus blocks were used to evaluate precision, sensitivity for detection, and efficiency of five sampling methods. The number of samples needed to reach a 0.25 standard error-mean ratio was estimated using Taylor's power law and used to compare precision among sampling methods. Comparison of detection sensitivity and time expenditure (cost) between stem-tap and other sampling methodologies conducted consecutively at the same location were also assessed. Stem-tap sampling was the most efficient sampling method when ACP densities were moderate to high and served as the basis for comparison with all other methods. Protocols that grouped trees near randomly selected locations across the block were more efficient than sampling trees at random across the block. Sweep net sampling was similar to stem-taps in number of captures per sampled unit, but less precise at any ACP density. Yellow sticky traps were 14 times more sensitive than stem-taps but much more time consuming and thus less efficient except at very low population densities. Visual sampling was efficient for detecting and monitoring ACP at low densities. Suction sampling was time consuming and taxing but the most sensitive of all methods for detection of sparse populations. This information can be used to optimize ACP monitoring efforts.

Vector control is widely viewed as an integral part of disease management. Yet epidemiological theory suggests that the effectiveness of control programs at limiting pathogen spread depends on a variety of intrinsic and extrinsic aspects of a pathosystem. Moreover, control programs rarely evaluate whether reductions in vector density or activity translate into reduced disease prevalence. In areas of California invaded by the glassy-winged sharpshooter (Homalodisca vitripennis Germar), Pierce's disease management relies heavily on chemical control of this vector, primarily via systemic conventional insecticides (i.e., imidacloprid). But, data are lacking that attribute reduced vector pressure and pathogen spread to sharpshooter control. We surveyed 34 vineyards over successive years to assess the epidemiological value of within-vineyard chemical control. The results showed that imidacloprid reduced vector pressure without clear nontarget effects or secondary pest outbreaks. Effects on disease prevalence were more nuanced. Treatment history over the preceding 5 yr affected disease prevalence, with significantly more diseased vines in untreated compared with regularly or intermittently treated vineyards. Yet, the change in disease prevalence between years was low, with no significant effects of insecticide treatment or vector abundance. Collectively, the results suggest that within-vineyard applications of imidacloprid can reduce pathogen spread, but with benefits that may take multiple seasons to become apparent. The relatively modest effect of vector control on disease prevalence in this system may be attributable in part to the currently low regional sharpshooter population densities stemming from areawide control, without which the need for within-vineyard vector control would be more pronounced.

Field and laboratory experiments were conducted to elucidate various factors influencing the temperature-dependent larval eclosion of winter moth, Operophtera brumata L, in New England. We found no difference in duration of the embryonic stage of eggs reared from larvae collected in Massachusetts (MA) and on Vancouver Island, British Columbia (BC), where winter temperatures are rarely below freezing. The number of growing degree days (GDD) required for larval eclosion declined with the number of days chilled in the laboratory and number of days below freezing in the field, confirming the findings of previous studies. Thus, eggs hatched with fewer GDD, when the spring came later than usual. Date of oviposition had no effect on date of hatch. Eggs laid by naturally occurring (feral) females hatched sooner, with lower GDD, than eggs from laboratory-reared females from MA and BC held on the same trees over the winter. South-facing eggs on the stems of trees hatched on average 1.6 days sooner than north-facing eggs. GDD calculated from bihourly measures of temperature were 15% greater than GDD estimates based on the average of daily maximum and minimum temperatures, as used by many GDD estimates made for online sources. Over two years, the mean GDD in °C for hatch of feral eggs was 176.53 ± 6.35 SE based on bihourly temperature measurements, a 1 January start date, and a 3.9°C developmental threshold. This value varied markedly, however, between the two years.

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is a key pest of many horticultural and agronomic crops in the western United States. Despite its well documented pest status, many aspects of the basic biology, including overwintering ecology, of L. hesperus are poorly understood. We examined the influence of eight constant temperatures from 10 to 35°C on survival of nondiapausing adult L. hesperus held with or without food, and the consequences of exposure to an extended period at 10°C on subsequent reproduction. Survival analyses indicated that, on average, fed insects tended to live longer than unfed insects, females lived longer than males, and the survival time decreased with increasing temperature. Nonlinear regressions indicated that median survival for insects grouped by gender and feeding status declined exponentially with increasing temperature. Survival functions for combinations of insect class (gender and feeding status) and temperature were adequately described by the respective two-parameter logistic functions. When adults were held for 9 d at 27°C with food after a 33-d period at 10°C either with or without food, no deleterious effects of prior starvation on propensity to mate or fecundity were demonstrated. These findings indicate that when temperatures are low, nondiapausing L. hesperus adults are capable of extended host-free survival with little or no impact on subsequent reproduction. Our findings suggest the current understanding of L. hesperus overwintering dynamics is incomplete. In addition, our results provide quantitative baseline information to facilitate more comprehensive investigation of the ecology of L. hesperus overwintering.

Micronutrients are important for metabolic processes and structures in insects. How termites obtain micronutrients from the environment is not fully understood. It has been suggested that lower subterranean termites of Rhinotermitidae only gain their nutrients from their food sources. However, for subterranean termites, soil offers a potential source of micronutrients. This study tested the hypothesis that subterranean termites acquire micronutrients from the soil. Laboratory colonies of Reticulitermes flavipes Kollar were reared in arenas in which the levels of micronutrients, food, and soil were varied. The results showed that the micronutrients Ca (Calcium), Fe (Iron), Mg (Magnesium), and Mn (Manganese) were obtained from the soil, Cu (copper) was obtained by the food source, and K (Potassium) and Zn (Zinc) showed no differences between treatments. The results of this experiment suggest that subterranean termites can acquire micronutrients from the soil as well as other food sources.

We present a general and flexible mathematical model (called SANDY) that can be used to describe many biological phenomena, including the phenology of arthropods. In this paper, we demonstrate how the model can be fitted to vital rates (i.e., rates associated with development, survival, hatching, and oviposition) of the two-spotted spider mite (Tetranychus urticae (Koch)) exposed to different constant temperatures ranging from 15°C to 37.5°C. SANDY was incorporated into an age-, stage- and sex-structured dynamic model, which was fitted to cohort life-tables of T. urticae conducted at five constant temperatures (15, 20, 25, 30, and 35°C). Age- and temperature-dependent vital rates for the three main stages (eggs, immatures, and adults) constituting the life-cycle of mites were adequately described by the SANDY model. The modeling approach allows for simulating the growth of a population in a variable environment.We compared the predicted net reproductive rate (R₀) and intrinsic rate of natural increase (r_m) at fluctuating temperatures with empirical values obtained from life-table experiments conducted at temperatures that changed with a daily amplitude (±0, ±3, ±6, ±9, and ±12°C) around an average of 22°C. Results show that R₀ decreases with increasing amplitude, while r_m is more robust to variable temperatures. An advantage of SANDY is that the same simple mathematical expression can be applied to describe all the vital rates. Besides, the approach is not confined to modeling the influence of a single factor on population growth but allows for incorporating the combined effect of several limiting factors, provided that the combined effect of the factors is multiplicative.

Allocation of larval nutrients affects adult life history traits in insects. This study assessed the effect of moth age and wing loading on flight capacity in an outbreaking forest lepidopteran, Malacosoma disstria Hübner . Insects were collected from high and low density populations after larval feeding, and flight capacity was tested directly with flight mills and indirectly through the allometric relationship between wing area and body size. Insects from these same populations collected as eggs and fed with a synthetic diet in the laboratory were tested in a separate experiment. Male moth propensity to fly increased with wing loading only when moths were collected as pupae after feeding in the field at high population densities. Moth age and wing loading did not affect the distance flown by male moths in any of the population density—nutrient regime combinations tested. Energy use increased with flight distance in both experiments. The slope of the allometric relationship between wing area and body mass did not differ from isometry when moths were collected as pupae after feeding at low and high population densities in the field. The slope of this relationship was steeper for males collected from high than low population densities. There was no allometric relationship between wing area and body mass of moths collected from these same populations as eggs and fed ad libitum in the laboratory as larvae. The results suggest that male M. disstria can allocate resources to different life history traits in response to differences in population density.

Several pine bast scales (Hemiptera: Matsucoccidae) are important pests of pine trees in the Northern Hemisphere. Some species are invasive and cause significant economic and environmental impacts. Such is the case with Matsucoccus feytaudi Ducasse, an invasive pest of maritime pine forests in Southeastern France, Italy, and Corsica. The ladybird Iberorhyzobius rondensis (Eizaguirre) is a recently described species that is endemic to the Iberian Peninsula and is a potential candidate for the biological control of M. feytaudi. However, little is known of the biology of I. rondensis. As part of the risk assessment study for a classical biological control program, the phenology and reproductive mechanisms of the beetle were analyzed. I. rondensis is univoltine and is seasonally synchronized with the phenology of the prey M. feytaudi, which is also univoltine. An obligatory reproductive diapause of 5–6mo and the need to feed on the eggs of the prey to begin oviposition emerged as the two primary mechanisms that assure life cycle synchronization of the ladybird with its prey. Female fecundity was also higher when the ladybirds were fed M. feytaudi eggs. Life cycle synchronization with M. feytaudi and reproduction triggered by consumption of prey eggs indicate that I. rondensis is a promising biological control agent of the pine bast scale.

The polyphagous navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), is the most destructive pest of nut crops, including almonds and pistachios, in California orchards. Management of this insect has typically been a combination of cultural controls and insecticide use, with the latter increasing substantially along with the value of these commodities. Possibly associated with increased insecticide use, resistance has been observed recently in navel orangeworm populations in Kern County, California. In studies characterizing a putatively pyrethroid-resistant strain (R347) of navel orangeworm, susceptibility to bifenthrin and β-cyfluthrin was compared with that of an established colony of susceptible navel orangeworm. Administration of piperonyl butoxide and S,S,S-tributyl phosphorotrithioate in first-instar feeding bioassays with the pyrethroids bifenthrin and β-cyfluthrin produced synergistic effects and demonstrated that cytochrome P450 monooxygenases and carboxylesterases contribute to resistance in this population. Resistance is therefore primarily metabolic and likely the result of overexpression of specific cytochrome P450 monooxygenases and carboxylesterase genes. Resistance was assessed by median lethal concentration (LC₅₀) assays and maintained across nine generations in the laboratory. Life history trait comparisons between the resistant strain and susceptible strain revealed significantly lower pupal weights in resistant individuals reared on the same wheat bran-based artificial diet across six generations. Time to second instar was greater in the resistant strain than the susceptible strain, although overall development time was not significantly different between strains. Resistance was heritable and may have an associated fitness cost, which could influence the dispersal and expansion of resistant populations in nut-growing areas in California.

The effects of long-term mass rearing of laboratory insects on ecologically relevant traits is an important consideration when applying research conclusions to wild populations or developing management strategies. Laboratory strains of the gypsy moth, Lymantria dispar (L.), an invasive forest pest in North America, have been continuously reared since 1967. Selection on these strains has enhanced a variety of traits, resulting in faster development, shorter diapause, and greater fecundity. As in many mass-reared insects, laboratory strains of the gypsy moth are also reared exclusively on artificial diets that lack much of the phytochemical and nutritional complexity associated with natural foliage.We tested for differences in growth and development of wild gypsy moth populations from across the invasive range in comparison to laboratory strains when reared on artificial diet and a preferred foliage host species, northern red oak (Quercus rubra L.). Overall, caterpillars reared on foliage had higher survival and faster development rates, with smaller differences among populations. When reared on artificial diet, laboratory strains had the highest performance as expected. The response from the wild populations was mixed, with two populations performing poorly on artificial diet and another performing nearly as well as the laboratory strains. Performance on diet was enhanced when larvae received cubed portions changed regularly, as opposed to filled cups. Understanding these relationships between food source and population performance is important for informing studies that examine population comparisons using wild and laboratory- reared strains.

Despite the medical importance of Paederus beetles, no studies have studied the influence of the abiotic factors on the flight activity and nighttime dispersal of these insects in Brazil. Therefore, the influence of both climatic factors and moon phase on black-light catches of Paederus rove beetles was investigated. Paederus beetles were attracted to a black light source hourly from 1800 to 0600 hours, and data on weather conditions as well as moon phase data were taken for every sampling date. Overall, 543 individuals of Paederus beetles belonging to four species were captured: P. protensus, P. columbinus, P. brasiliensis, and P. mutans. Paederus beetles were mostly active in the warmest parts of the studied nights. Variations in nighttime temperature, relative humidity, wind speed, cloud cover, and moon phases appear not to affect Paederus flight. The diurnal temperature was observed to affect the night hourly dispersal of Paederus rove beetles as well as their distribution pattern during the entire period of study. The true environmental condition responsible for Paederus beetles seasonal pattern and daily night dispersal in northeastern Brazil were the annual moisture and drought cycles and the diurnal maximum temperatures, respectively. Significant trap catches were observed in the earliest hours after sunset (1800–2100), and people must be aware of this fact, as it can notably increase the risk of acquiring linearis dermatitis from the contact with large numbers of active Paederus.

In the southern plains of the United States, winter-adapted canola (Brassica napus L.) is a recently introduced annual oilseed crop that has rapidly increased in hectares during the past 10 yr. Winter canola fields are infested annually with populations of Brevicoryne brassicae (L.) and Lipaphis erysimi (Kaltenbach), and these Brassica specialists are known to sequester plant volatiles from host plants, producing a chemical defense system against predators. Myzus persicae (Sulzer) is also common in winter canola fields, but as a generalist herbivore, does not sequester plant compounds. These three aphid species are expected to affect predator survival and development in very different ways. We conducted laboratory studies to 1) determine whether Hippodamia convergens (Guérin-Mé neville) and Chrysoperla carnea (Stephens) larvae demonstrate feeding preferences among winter canola aphids and 2) describe the suitability of these prey species. Predators demonstrated no significant preference among prey, and each aphid species was suitable for predator survival to the adult stage. However, prey species significantly affected development times and adult weights of each predator species. Overall, predator development was delayed and surviving adults weighed less when provided with L. erysimi or B. brassicae, which sequestered high levels of indole glucosinolates from their host plants. Our results indicate that although common winter canola aphids were suitable prey for H. convergens and C. carnea, qualitative differences in nutritional suitability exist between Brassica-specialist aphids and the generalist M. persicae. These differences appear to be influenced by levels of sequestered plant compounds that are toxic to aphid predators.

The objective of this study was to document current areas of subterranean termite activity in Wisconsin and to evaluate genetic characteristics of these northern, peripheral colonies. Here, amplified fragment-length polymorphism was used to characterize levels of inbreeding, expected heterozygosity, and percent polymorphism within colonies as well as genetic structure among populations sampled. Genetic analysis revealed two species of termites occur in Wisconsin, Reticulitermes flavipes (Kollar) and Reticulitermes tibialis Banks, both found in the southern half of the state. Colonies of both species in Wisconsin are thought to represent the northern boundary of their current distributions. Measurements of within colony genetic variation showed the proportion of polymorphic loci to be between 52.9–63.9% and expected heterozygosity to range from 0.122–0.189. Consistent with geographical isolation, strong intercolony genetic differences were observed, with over 50% of F_ST values above 0.25 and the remaining showing moderate levels of genetic differentiation. Combined with low levels of inbreeding in most collection locations (F_IS 0.042–0.123), we hypothesize termites were introduced numerous times in the state, likely by anthropogenic means. We discuss the potential effects of these genetic characteristics on successful colony establishment of termites along the northern boundary compared with termites in the core region of their distribution.

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is a major pest of cotton (Gossypium hirsutum L.) in the state of Mississippi. Economic data indicate that L. lineolaris is a more serious pest of cotton in the Delta region of Mississippi than in the Hills region; however, little data exist comparing the two populations. Two experiments were undertaken to compare L. lineolaris from these two geographically distinct regions. In the first experiment, colonies of L. lineolaris from each region were reared in the laboratory under controlled conditions and measurements of development time, survivorship, fecundity, and hatch rate were compared. The geographic region of origin had no effect on any of the variables measured; however, the diet used for rearing had a significant effect on all variables except hatch rate. In the second experiment, part of the cox1 gene of the L. lineolaris mitochondrial genome was compared between the two populations to examine possible genetic differences between L. lineolaris from the two regions of Mississippi. Data revealed two cox1 clades in the Delta region and only one cox1 clade in the Hills region. Taken together, the data do not explain the reason for the differences in the severity of damage to cotton in the two regions.

The cotton mealybug Phenacoccus solenopsis Tinsley is an emerging invasive insect pest. Since its first report as a pest in the United States in 1991, it has invaded and colonized more than 23 countries over the past century. It was first recorded from Pakistan in 2006 and from China in 2008. In this study, we performed field surveys from 2010 to 2012 and obtained mtCOI sequences from specimens across China and Pakistan, then compared them with already available mtCOI sequences from additional Asian and North American countries. Our genetic analysis provides evidence that P. solenopsis should be classified into two groups, one of which is found only in the United States, and the other found only in Asia. The Asian group contains nine unique haplotypes, two of which have invaded and spread across China, Pakistan, India, and Vietnam over the last 4–6 yr. Our genetic analysis also indicates that P. solenopsis has a close relationship with the parasitoid wasp Aenasius bambawalei Hayat, providing preliminary evidence of a congruent spread of this mealybug and its parasitoids across China.

Figure 1 was incorrect. Below is the correct figure.

On p. 1391 of my paper (Smith 2014), the line “DT = ln(2)/λ” should be “DT = ln(2)/r_m.” The calculations for doubling time used the correct equation.

Corresponding author, e-mail: Link.smith@ars.usda.gov